The pharmaceutical use of antibodies has increased over the past years. In many instances such antibodies are injected via the intravenous (IV) route. Unfortunately the amount of antibody that can be injected via the intravenous route is limited by the physico-chemical properties of the antibody, in particularly by its solubility and stability in a suitable liquid formulation and by the volume of the infusion fluid. Alternative administration pathways are subcutaneous or intramuscular injection, which offer potential advantages in terms of patient compliance and ease of administration. These injection pathways require high protein concentration in the final solution to be injected.
Accordingly, there is a desire to provide highly concentrated, stable pharmaceutical formulations of therapeutically active antigen binding proteins such as antibodies for subcutaneous injection. The advantage of subcutaneous injections is that it allows the medical practitioner to perform it in a rather short intervention with the patient. Moreover the patient can be trained to perform the subcutaneous injection by himself. Such self-administration is particularly useful during maintenance dosing because no hospital care is needed (reduced medical resource utilization). Usually injections via the subcutaneous route are limited to approximately 2 mL. For patients requiring multiple doses, several unit dose formulations can be injected at multiple sites of the body surface.